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This blog post won't be about the sigrok software for a change. Instead, it is meant to introduce a little hobby project for a tiny DIY FX2 based Open Hardware logic analyzer (that you can use with sigrok, of course): fx2grok-tiny.

The original plan for a tiny logic analyzer was devised by me (Uwe Hermann) in 2012, but being a sigrok developer, I've concentrated on various more important tasks, features, and bugs in the sigrok stack for quite a while. Near the end of 2017 I finally got around to finishing this project.

So the plan was to make an 8-channel, 24MHz FX2 based logic analyzer that is
* Open Hardware (CC-BY-SA 4.0 license for schematics and layout),
* uses Open Source EDA tools (KiCad),
* uses Open Source software on the PC side (libsigrok, PulseView),
* uses Open Source firmware on the FX2 microcontroller (sigrok-firmware-fx2lafw),
* and is as tiny as possible

As you probably know, there are tons of (larger) FX2 based LAs around already, so there's no point to make just yet another one of those. What's unique about this one is that it's completely open, and it may just be the smallest logic analyzer on the planet (don't quote me on that, though).

The original plan was to fit all required components in a 13x13mm PCB, but the final device ended up being even a little smaller, 11x11mm. The limiting factors are the Cypress CY7C68013A (a.k.a. FX2) chip itself (QFN-56, 8x8mm) plus the micro USB connector and 24MHz crystal, so getting it even smaller than 11x11mm is not easily possible.

The design intentionally sacrifices a lot of things (no EEPROM, no input protection, various Cypress hardware recommendations are ignored) in order to be able to make it very tiny.

This project was a lot of fun for me. Being a software guy, I learned quite a bit about creating schematics and doing PCB layouts (in KiCad), PCB manufacturing details, solder stencil and solder oven usage, and lots more. I also learned that when you screw up the FX2 footprint, you'll get magic smoke (that's why the final version is 0.2, I had to completely reroute the whole PCB after fixing the footprint).

If you're wondering whether you can order fx2grok-tiny devices or bare PCBs, the answer is no. This is a purely non-commercial hobby project by a single guy. You can, however, make your own devices since everything is open and documented.

As an "enclosure" of sorts you can simply use e.g. transparent heatshrink tube. I'm also working on a tiny 3D printable enclosure, we'll see how that goes.

As for the probe cables there are various options as well. You can use a nice Samtec cable or just solder a DIY cable out of generic ribbon cable. In both cases, you'll have to use a crimp tool so you can later attach the usual logic analyzer grippers.

The fx2grok wiki page has a lot more details and photos about the device (including a BOM, you can get pretty much all required parts from e.g. Digikey) and how to assemble it.

You can also get the whole KiCad project, schematics, layout, and Gerber files via git:

$ git clone git://sigrok.org/fx2grok

There's also a blue LED on the PCB for the obligatory blinkenlights, btw. It'll blink during a logic analyzer acquisition and just light up constantly in idle.

For the future I'm looking into maybe creating an even smaller FX2 based logic analyzer named fx2grok-bga, which employs (you guessed it) the BGA version of the FX2. The BGA chip is 5x5mm (instead of 8x8mm for the QFN version). Soldering this is going to be a bit more tricky though, we'll see how it goes.

There are also other fx2grok variants being worked on, e.g. fx2grok-flat by Piotr Esden-Tempski, more about that in another blog post.

And with that, we now support a total of 77 different protocol decoders. There are some more in the pipeline for the next releases, and we get contributed decoders on a pretty regular basis these days, which is awesome! If you're working on additional PDs, please send patches our way!

Decoders using PD v3 API can benefit from both readability improvements as well as performance improvements. Up to 10x speedup has been measured in some situations (depends a lot on the decoder, the amount of data, the amount of edges in the signals, and the amount of oversampling).

The majority of all decoders have been converted to PD API v3.

For the time being, both APIs (2 and 3) will remain supported until all decoders have been converted to API version 3. Then, support for API version 2 will be dropped.

There is now support for specifying the (assumed) initial pin states before the first sample that is being decoded. This can be set to 0/low, 1/high, or to "use the same value as in the first sample". This is very useful for some setups where decoders need to wait for edges.

See the NEWS file for a much more detailed list of changes, or browse the git history for even more details.

sigrok-firmware-fx2lafw

This release adds open-source FX2 firmware for the Hantek 6022BL USB scope/LA (similar, but not quite compatible to the already-supported Hantek 6022BE).

See the NEWS file for a much more detailed list of changes, or browse the git history for even more details.

sigrok-cli

The sigrok-cli command-line utility has seen a few improvements and bugfixes as well.

The new -L|--list-supported option shows the supported drivers, modules, and decoders (this was previously listed as part of the -V|--version output).

There's now support for running multiple decoder stacks on the capture at the same time by specifying multiple -P|--protocol-decoders options; the old -S option is no longer needed and has been removed.

See the NEWS file for a more detailed list of changes, or browse the git history for even more details.

PulseView

The PulseView GUI has seen a pretty large set of improvements as well.

There's a facility to add multiple sessions and views in PulseView now:

Sessions represent individual files/device instances. Each session is represented as a tab in PulseView.

Views are different data representations of one specific session. For example, different views of a session can have different zoom levels, can be scrolled to different positions, etc. Each view is a dock window within the respective session's tab.

The view docks can be repositioned, resized and extracted out into their own individual windows.

Sessions and views are partially saved and restored when PulseView exits/starts. Not all information is restored yet, though (e.g. decoders).

Various new or improved features have been added:

Support for saving analog data to .sr files.

Support for showing the sampling points in traces.

Various UI and usability improvements.

Various improvements for analog traces and their presentation.

There's a global settings menu now with config options for various PulseView behaviours.

There have also been a large number of other random new features, bugfixes, documentation fixes, portability fixes, build system improvements, and so on.

See the NEWS file for a much more detailed list of changes, or browse the git history for even more details.

There are also a bunch of regressions and/or known bugs and missing features we'll be working on for the next minor bugfix release. If you notice any issues that haven't been reported yet, please file a bug.

Thanks a lot to everyone who has contributed to any of the sigrok projects to make these releases happen! This wouldn't have been possible without the help of the numerous contributors!